Paste storage plan floated for Kensington tailings issue

New proposal would require less wastewater treatment than dry stack

Posted: Friday, November 16, 2007

By AMANDA FEHDJUNEAU EMPIRE

Closed-door meetings between Coeur Alaska and three conservation groups have resulted in a plan to ask the U.S. Forest Service to consider a different method and place for storing tailings from the Kensington gold mine.

"What is significant here is these players are not at odds for the moment, they are saying they have something that is worth considering," Juneau Mayor Bruce Botelho told the Juneau Empire.

Coeur is now proposing to store the tailings at Comet Beach, using paste tailings instead of dry stacking at the mine, which is about 45 miles northwest of downtown.

Paste tailings are thicker than the watery slurry that comes out of a mill and require less wastewater treatment than a dry stack. Tailings are the waste rock from ore after the metal is extracted.

"The conservation groups believe that the potential adverse environmental impacts of the Comet Beach site are less than the impacts of the alternative sites that have been identified," a statement from Botelho said.

Botelho made clear the agreement does not imply any endorsement of the plan by the Southeast Alaska Conservation Council, Lynn Canal Conservation and Juneau's Sierra Club. The groups successfully sued to block Kensington's previous plan to put the tailings into 23-acre Lower Slate Lake on the grounds it violated the Clean Water Act.

Representatives of SEACC and Coeur referred all requests for comment to Botelho on Thursday.

Botelho's statement also said the groups "have preserved all of their legal rights pending the final permitting of the mine."

"It's important to underscore that the parties have made no decision that is binding on any agency, nor for that matter has any party committed to this particular site or methodology. There's no done deal, there is a proposal that will be examined and which the public will have an opportunity to comment on," Botelho told the Empire.

The plan comes as a result of several closed-door meetings between the mine's owners and the conservation groups.

Kensington must now seek the appropriate permits for the plan from various regulatory agencies.

Comet Beach is on the other side of a mountain from where Coeur built a $200 million mill. Kensington representatives have said in the past that storing tailings at the beach would be too expensive and logistically difficult.

Under a past proposal by the mine, all the mine's facilities, including the mill and a dry stack for tailings, would have been at Comet Beach.

Doing a paste disposal might make the project more economically feasible, said Tom Crafford, the large mine permitting manager at the Department of Natural Resources.

"A paste disposal would mean you could pump the material over to (the beach), you'd have a relatively modest amount of processed water that you'd have to treat before it would be released to the environment and you would avoid both the capital and operating costs of constructing, operating and maintaining a filter plant to dewater the tailings further," Crafford said.

Both paste and dry stack tailings require a much larger footprint on the landscape than the Lower Slate Lake proposal, which was thrown out by the 9th U.S. Circuit Court of Appeals, Crafford said.

When asked why the meetings were secret, Botelho said that in sensitive negotiations, confidentiality allows people to float ideas that otherwise might make it awkward for them to deal with constituents such as shareholders or members.

"The very act of negotiating and being willing to try and reach resolution inherently involves taking risk and being able to test ideas, trying to bounce it off another person, that you wouldn't venture if every comment you made might end up appearing on the front page of the newspaper or on a television news channel," Botelho said.